Global chaotic parameters of heart rate variability during mental task

We aimed to evaluate the novel chaotic global techniques of heart rate variability (HRV) analysis during a specific autonomic test, the mental arithmetic overload test. These are spectral detrended fluctuation analysis and spectral multi‐taper method; in addition to spectral entropy. We analyzed 24 healthy male students—all nonsmokers, aged between 18 and 22 years old. HRV was analyzed in the following periods: control protocol—the 10‐min periods before the performance of the task and the 5‐min periods during the performance of the test. Following tests for normality; Kruskal–Wallis technique and principal component analysis—it was decided that this type of mental stimulation did not lead to significant changes in any of the seven combinations of chaotic globals. In conclusion, it was suggested that the time‐series be increased to 1000 RR intervals (at least 20 min of electrocardiographic data) and standard nonlinear methods be introduced in combination with spectral factors as a way of increasing the statistical significance. © 2015 Wiley Periodicals, Inc. Complexity 21: 300–307, 2016